The present invention relates to antennas and more particularly to non-metallic conductive antennas and antennas constructed of both non-metallic conductive materials and metallic conductive materials.
In the past, the band width of metallic conductor antennas has been restricted due to the increase in standing wave ratio over the operating frequencies of the antenna. This occurs as a practical matter because the change in antenna frequency is reflected as a change in the standing wave ratio on the transmission line. This would not occur if the antenna impedance were purely resistant and constant regardless of frequency. The principal cause of the change in the standing wave ratio is the change in the reactive components of the antenna impedence when the frequency is varied. If the reactance changes rapidly with frequency the standing wave ratio will rise rapidly off the center frequency, but if the rate of reactance change is small the shift in standing wave ratio likewise will be small.
The present invention takes advantage of this electrical principal by using a non-metallic conductor such as carbon or graphite as the primary component of the antenna to minimize the reactive components of the antenna over a large band width therefore the standing wave ratio stays low over a very large band width.
Since carbon, graphite, and other non-metallic conductors can withstand high temperatures without a large change in conductive characteristics, the antenna constructed of such material would be conducive for use in space vehicles, especially during re-entry into the earth's atmosphere, when high temperatures are generated.